Ballpoint pens currently on the market generally have a rigid structure, including a round or prismatic body and a cartridge containing the ink and terminating, at one end, in a ballpoint pen tip from which a ball extracts ink and applies it to the substrait.
Such rigid structures are often uncomfortable to carry, e.g. in the front pockets of trousers or skirts.
Occasionally a ballpoint pen may be carried in the back pocket of a garment so that it may bend or break when the person wearing the garment sits down, thereby irreparably damaging the pen and causing substantial damage to the garment or leakage of the ink.